Fertilizing Effect of Swelling Clay Materials on the Growth and Yield of Bean “Phaseolus vulgaris” on the Sandy Ferruginous Soils from Mafa Tcheboa (North Cameroon, Central Africa)

Amendment of sandy ferruginous soils by swelling clay materials can be a promising solution to improve their fertility and thus enhance crop yield. In this study which aims at valorization swelling clay materials in the mineral fertility of ferruginous soils, a pot experiment was conducted using ferruginous soils from northern Cameroon which were sampled at Mafa Tcheboa, and amended by swelling clays materials collected also in the North Cameroon. The effect of swelling clay application on the growth and productivity of common bean “Phaseolus vulgaris” was followed by means of measures of growth and yield parameters. An experimental design which consisted in a randomized complete block design (RCBD) is constituted of two series of five treatments each one: the control (ST), the control mixed with 300 g of clay before sowing (SAS), the control with 20 g of clay in the hole of sowing (STS), the control with 20 g of clay at the germination stage (SAL) and the control with 20 g of clay at the approaching flowering stage (SAF). Each treatment was replicated ten times in every serie. The control treatment is only soils of Mafa Tcheboa without any clay application; they are sandy, acid and display a low CEC with kaolinite as main clay mineral, while swelling clay materials are basic and display a cation exchange capacity (CEC) 3 times higher than that of controls, and made up mainly of smectites. On the geochemical point of view, both materials are constituted mainly by SiO2, Al2O3, Fe2O3 as major elements; and Ba, Zr and Sr as traces elements. All the treatments were irrigated with 250 ml of water one time all two days during the growing stage. The growth and yield components were measured every three days. 14204 measures of growth components and 35440 measures of yield components were made. The results indicate an important increase of stem length and its branches, leaves number, leaflet length, leaflet width, main root length and number of its ramifications in the soils amended by swelling clay materials. About 2.5 times of yield were obtained from those treatments compared to control in one hectare. The germination stage and the flowering stage are the best periods to apply swelling clay materials. The overall results indicate that swelling clay material can be used to enhance bean’s crop yield in ferruginous soils from Mafa Tcheboa and therefore are interesting alternative petrofertilizers to very expensive chemical fertilizers.